sean,
It's really quite simple.
Before going to the trouble of hooking everything up, see if your 2 CDs will boot on the "host" computer you will be using. For example, the PB G4 15" Titanium released in '03 was the last powerbook to run MacOS 9.2.2 natively. All computers that can no longer boot into 9.2.2 can still run 9.2.2 inside 10.x in emulation and 9.2.2 is known as Classic in this configuration.
-The host computer must be a PPC that supports both Tiger and 9.x so both the Tiger and 9.x CD you have will boot. With the host computer running...
-Connect the Pismo (target) to the host, then start the the Pismo in FireWire Target Disk Mode (FTDM); be sure you are using a 6-pin FireWire cable.
http://support.apple.com/kb/HT1661
-As the above tech article describes, the Pismo's HD will appear on the host's desktop and you treat it like it was just an external drive.
-Now load the Tiger DVD in the host and restart; OSX requires the computer be booted to the OSX DVD for installation.
-Immediately go to the Disk Utilities in the menu bar, open Disk Utility, select the Pismo's HD in the left window, then select Erase on the right side. Make sure you have the correct selection...you don't want to erase the host's HD.
-Now quit Disk Utility and continue with the installation. When complete, Tiger will want to boot to the Pismo's HD to finish up. This means the host computer will be using the Pismo's HD instead of its internal HD...this is normal.
-Select the host's internal HD in the Startup Disk panel in System Preferences and restart. You always want to leave the host's startup volume with the correct selection...its internal HD.
-Now load the 9.x CD and restart the host to this CD. All you have to do is select Clean Install.
http://support.apple.com/kb/HT1585?viewlocale=en_US
-Properly unmount the Pismo's HD from the host and shut down the Pismo which is in FWTDM. Now startup the Pismo and see how it runs.
Any questions, please ask.
If the above does not work because you can't boot your CDs, please post back with info on the PPC computer you are using as host...model and installed software.